"A reliable source of food is always under the ground, in the earth - good old worms," Grylls told Efron, handing the star one half of a worm he had just bitten in half. "'Just remember you've got to chew it - you don't want it wriggling all the way. Otherwise it might crawl out of like a weird orifice or something."

Turns out that worm was just an appetizer for the main course - a worm omelet with bird eggs, shells and all.

"Sometimes I cook up these wilderness meals and get quite excited, I think, ''You know what, this is gonna be amazing'," Grylls informed Efron. "But I'm not gonna sugarcoat it - this is one of the ones that I know is gonna suck." To his credit, Efron was a good sport, eating his worm omelet and, as expected, later describing it as "gross" and "bitter."

From what I've managed to gather online, worm omelets are reportedly a recipe often taught to British soldiers as a survival tactic. Back in 2003, a published study by The Royal Society found earthworms to be high in protein and calcium, as well as a source of iron, magnesium, potassium, phosphorus and copper. It's no wonder they're an easy go-to food if you're stranded somewhere - or sharing a cave with Bear Grylls.

But let's get to the part you've been waiting for: how to cook up your own worm omelet. Not surprisingly, there's a YouTube video for that.